Big Red Bath, by Julia Jarman and Adrian Reynolds

A lively story with lots of animals to spot, some nice repetitive rhyming text pitched at just the right level, and a plot (involving a very messy bathtime that gets out of hand) designed to appeal to toddlers. A lot of fun and one that gets hauled out for rereads a lot.

A great read aloud classic (my neice recommended it, so it must be good) with vivid illustrations conveying the boisterous activity that kids this age love to join in with.
Ben and Bella have a bath which soon gets crowded with a menagerie of animals from duck to hippopotamus, culminating in the bath flying up into the air and having to be towed back home...but in the end picture you will be wondering (well, your toddler will be) "did it all actually happen then, or was it just their imagination?", as it calms the mood right down in time for bed.